Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of the first image in a sequence for a display screen or portion thereof with transitional graphical user interface showing our new design;

FIG. 2 is a front view of the second image thereof;

FIG. 3 is a front view of the third image thereof;

FIG. 4 is a front view of the fourth image thereof; and,

FIG. 5 is a front view of the fifth image thereof.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-5. The process or period in which one image transitions to another forms no part of the claimed design.

The broken line showing of unclaimed portions of the transitional graphical user interface within FIGS. 1-5 forms no part of the claimed design, and the broken line around FIGS. 1-5 showing of the display screen or portion thereof is included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

CLAIM We claim the ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 